Case 3: P < PLvap (vapor phase)

All the liquid is vaporized.

We can apply θ=1 in the previous case; the volume of vapor is then:

In this case, the air volumetric fraction is:

And the fluid density:

This gives us the three cases:

Case	{liquid+vapor} bulk modulus ρliq+vap
Case 1:	P > PHvap
Case 2:	PLvap < P < PHvap
Case 3:	P < PLvap

And: